Thortveitite
Sc2Si2O7IMA symbol: Tvtgrandfathered
Thortveitite is a silicate mineral with the formula Sc2Si2O7, crystallizing in the monoclinic system. It has a Mohs hardness of 6-7, typically white, gray, green or red in color, a calculated density of 3.674 g/cm3. Its streak is grey.
Photos
Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | C 1 2/m 1 |
| Cell (Å, °) | a = 6.587, b = 8.547, c = 4.695; α = 90, β = 102.65, γ = 90 |
| Cell volume | 257.908 ų, Z = 2 |
| Axial ratios | 0.7707:1:0.5493calculated from COD 9001138 |
| Source structure | COD 9001138 (American Mineralogist, 1988) — 1 of 5 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.125 | 2.952 | 3.156 | 1.649 | 2.183 | 2.605 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 53.4 | 42.4 | 22.7 | 22.1 | 20.6 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9001138; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.674 g/cm³calculated from COD 9001138 |
|---|---|
| Hardness (Mohs) | 6-7single sourceDana's System, 3rd Appendix (1915) |
| Color | gray, green, red, whitesingle sourceDana's System, 3rd Appendix (1915) |
| Streak | greysingle sourceWikidata (CC0) |
Chemistry (calculated)
| Molecular weight | 258.08 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Sc 34.84%, Si 21.77%, O 43.4% |
Classification
| Nickel-Strunz (10th) | 9.BC.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.BC.05Wikidata (CC0) |
| Dana (8th) | 55.2.1a.4Wikidata (CC0) |